Construction work has resumed on the Dakota Access pipeline after the U.S. Army Corps of Engineers on Wednesday issued the last remaining easement the company needed to cross under Lake Oahe.

Meanwhile, a new lawsuit has been filed seeking to stop the construction work, but it was not filed by the Standing Rock Sioux Tribe. The suit was filed by the Cheyenne River Sioux Tribe Thursday in the District Court of Washington, D.C., seeking a preliminary injunction and a temporary restraining order for religious reasons.

Remi Bald Eagle, the Intergovernmental Affairs Coordinator for the Cheyenne River Sioux, said, “We are continuing to do everything we can legally to defend our treaty territory and our water.”

Bald Eagle said they want the government to continue with the Environmental Impact Statement President Barack Obama’s administration had announced it would engage two days before his administration ended.

“Our next step is to have our day in court and see if we can get the judicial system to realize they are the only thing standing between right and wrong in this situation, and afford us and our relatives on the reservation a chance to discuss what happened and what is going on,” he said. “Hopefully we can convince them of the need for the federal government to do a full environmental impact study so that we know what the impact of this is going to be, and that way the great Sioux Nation can make an informed decision.”

Judge James Boasberg did not immediately rule on the motion, but is set to hear arguments related to the motions at 2 p.m. Monday.

Dakota Access did not have an immediate statement on the matter, and has not yet filed a response to the Cheyenne Tribe’s motion in court. The company issued a statement late Wednesday night that it would “proceed expeditiously” to complete the pipeline now that the easement has been granted.

Company spokeswoman Vicki Granado said the company would begin construction “immediately.” The work to cross under Lake Oahe will take 60 days to complete, the company has previously said. It has already done all the preparation work to drill horizontally under the lake, and has put some oil in portions of the pipeline leading up to the crossing.

The pipeline was proposed to carry Bakken crude to Illinois, where it can more readily access the refineries that handle light sweet crude. Industry leaders have said it is vital to the oil and gas industry’s future in the region.

The Cheyenne River Tribe’s suit is in addition to those that have already been filed by the Standing Rock Sioux Tribe in federal court, which were also scheduled to be heard in court Monday.

The easement for Dakota Access was issued after President Donald Trump signed a memorandum directing the Army Corps to review and expedite the Dakota Access matter. Industry groups hailed the move, while environmental groups and the involved tribes vowed to fight it.

Public statements Trump made recently drew a sharp retort from the Standing Rock Sioux Tribe.

“President Donald Trump’s statements that he hasn’t heard any opposition to the Dakota Access pipeline reflect a distorted sense of reality, given the Standing Rock Sioux Tribe’s opposition inspired a global movement against the pipeline,” the media statement said.

Standing Rock Sioux Tribal Chairman David Archambault II had flown to Washington D.C. Tuesday to meet with the Trump administration and discuss the Tribe’s perspective, however, he canceled the meeting after hearing of the Army Corp’s notification to Congress about the easement.

“We sent a letter directly to Trump, have filed a legal challenge, and we stand with more than 360 Native Nations and millions of Americans who have voiced their opposition to the project,” he said. “The media has widely reported the President’s brazen conflict of interest to the pipeline, his complete disregard for Native Nations and our treaty rights is disrespectful.”

Archambault renewed calls for the federal administration to proceed with the Environmental Impact Statement they were promised by the Obama administration.

“We have asked for a fair, balanced, and lawful environmental impact statement directly to President Trump and through the courts,” he said. “The Governor, North Dakota’s congressional delegation and the entire world are keenly aware of the immense opposition to this project. We encourage our allies to exercise their First Amendment rights to remind President Trump where we stand on DAPL. Rise with Standing Rock.”